The invention relates to a microstructure with a first microstructure piece in the surface of which is formed at least one receiving recess, with at least one second microstructure piece having a connecting region engaging in the receiving recess and on which is arranged at least one electrical contact element, with at least one tongue having at least one counter-contact element arranged between the connecting region and a side wall of the receiving recess facing the latter in such a way that the contact element of the connecting region contacts the counter-contact element of the tongue with a flexible cable having at least one flat substrate layer made of an electrically insulating material and at least one strip conductor electrically connected to the counter-contact element arranged thereon and which is connected at a place spaced apart from the tongue to an electric circuit spaced apart from the first microstructure piece. The invention further relates to a process for assembling a microstructure.
Such a process is disclosed in EP 1 985 579 A2. In the process, provision is made of a first microstructure piece having a surface in which are formed several approximately rectangular receiving recesses with electrically insulated boundary walls. On each rim of each receiving recess on the first microstructure piece are arranged several tongues, which overlap a partial area of the respective receiving recess with their free ends. The tongues have counter-contact elements that are connected via strip conductors to the contact terminals arranged on the first microstructure piece. The contact terminals are connected via an ultraflexible cable to an electric circuit remotely arranged relative to the first microstructure piece.
For manufacturing the first microstructure piece, provision is initially made of a substrate on which a photomask is applied, which photomask has interruptions at the places where the receiving recesses will eventually be formed. The receiving recesses are then etched into the substrate. In another process step, the recesses are filled with a sacrificial layer. The surface of the configuration thus obtained is made level by removing material and then tongues are formed on the surface by depositing metal. A first tongue segment is arranged on the surface of the substrate and a second tongue segment is arranged on the sacrificial layer. At this point the sacrificial layer is removed. The first tongue segment remains connected to the substrate, whereas the second tongue segment overlaps the receiving recess at a distance from the floor thereof.
Further provision is made of a second microstructure piece, which has connecting regions fitting into the receiving recesses and needle-shaped shaft pieces arranged on said connecting regions. The shaft pieces are arranged in several rows and columns parallel to one another and are prismatically configured on each of their free ends spaced apart from their associated connecting region. On each shaft the second microstructure piece has several electrically conductive regions, each of which is electrically connected to a contact element arranged on the connecting region.
In another process step, the second microstructure piece is positioned relative to the first microstructure piece in such a way that the connecting region is opposite the receiving recess. The second microstructure piece is then displaced towards the first microstructure piece in order to introduce the connecting region in the receiving recess. The tongues are thus deflected in the receiving recess in such a way that each tongue contacts its respective associated contact element. Afterwards the microstructure pieces are attached to one another.
A disadvantage resides in the process in that the tongues are relatively laborious and time-consuming to manufacture. Furthermore, connecting the cable to the first microstructure piece involves a certain degree of effort. Hence the microstructure is relatively expensive to manufacture.
The object is therefore to create a microstructure of the aforementioned type that permits a simple and economical construction. Another object is to devise an easily carried out process for assembling a microstructure.
With regard to the process, this object is achieved by the following steps:
It is thus possible to manufacture the tongues along with the cable and separately from the microstructure pieces and then position them along with the cable on the microstructure pieces. Advantageously it is thus possible to dispense with a laborious filling of the receiving recess arranged on the first microstructure piece with a sacrificial layer and with the process steps of applying the tongue on the first microstructure piece and removing the sacrificial layer. Preference is given to the dimensions of the receiving recess being within a range of 10-5000 μm and particularly within a range of 100-1000 μm.
Preference is given to positioning the flexible cable on the first microstructure piece in such a way that the at least one contact element and the at least one counter-contact element are spaced apart from the first microstructure piece by the substrate layer. The strip conductor and the counter-contact element of the tongue are then electrically insulated from the first microstructure piece by the substrate layer. The surface of the first microstructure piece facing the cable and even the entire microstructure piece can then be composed of an electrically conductive material, particularly a semiconductor material.
In a preferred embodiment of the invention, the first microstructure piece has an adhesive layer on its surface facing the cable in the preassembly position, and the first microstructure piece in the preassembly position and the cable are displaced towards one another in such a way that the cable touches and then adheres to the adhesive layer. The assembly of the microstructure is then even more easily carried out.
In another advantageous embodiment of the invention, the cable has an adhesive layer on its surface facing the first microstructure piece in the preassembly position, and the first microstructure piece in the preassembly position and the cable are displaced towards each other in such a way that the first microstructure piece touches and then adheres to the adhesive layer. This measure also enables a simple and quick assembly of the microstructure.
It is advantageous if the cable has at least one perforation, the at least one tongue being connected with the edge region thereof in such a way that it extends into the perforation and/or overlaps the latter at least area-wise, wherein the cable in the preassembly position is positioned relative to the receiving recess in such a way that the perforation overlaps the receiving recess, and wherein the connecting region, under the deflection of the tongue, is inserted through the perforation and into the receiving recess. Preference is given to the dimensions of the perforation corresponding to the cross-sectional dimensions of the connecting region, thus ensuring the attachment of the cable to the second microstructure piece in the correct position.
Preference is given to the second microstructure piece having at least one shaft piece connected to the connecting region, which shaft piece has at least one electrically conductive region that is electrically connected to the contact element. Such a microstructure can be used in neurophysiology for the intracortical, extracellular tapping of information on a neuronal network. The information can then be further processed as electrical signals.
With regard to the microstructure mentioned in the introduction, the aforementioned object is achieved by the integral configuration of the tongue with the cable.
The tongue can then be easily manufactured along with the cable and the microstructure pieces can then be processed independently of the latter. Afterwards the cable and the microstructure pieces can be easily assembled.
In an advantageous embodiment of the invention, the at least one strip conductor and the at least one counter-contact element are spaced apart from the first microstructure piece by the substrate layer. The tongue and the strip conductor are thus electrically insulated from the first microstructure piece by the substrate layer. Hence the first microstructure piece can be composed of an electrically conductive material.
In a preferred embodiment of the invention, the cable has at least one perforation that penetrates the cable perpendicular to its extension plane, wherein the tongue is aligned perpendicular to the plane spanned by the perforation and connected to an edge region of the perforation at its end remote from the conductive region. The cross-sectional dimensions of the perforation can then be adapted to the cross-sectional dimensions of the connecting region and the tongue in such a way that the perforation can be used as a positioning aid when assembling the microstructure pieces and the cable.
An adhesive layer facing the cable by means of which the cable adheres to the first microstructure piece is advantageously arranged on the first microstructure piece. The cable is then flatly and fixedly attached to the first microstructure piece via the adhesive layer.
It is advantageous if the tongue has a curvature between the edge region of the perforation and the contact element, and if the side wall of the receiving recess facing the tongue has an inclined surface and/or a step adjacent to the curvature, where the clearance between the side wall and a wall of the connecting region opposite said side wall increases from the floor of the receiving recess to the surface of the first microstructure piece. In this manner the cable is protected from excessive mechanical stress or kinking at the point where it is guided over the edge region of the perforation during the assembly of the microstructure.
In an advantageous embodiment of the invention, the cable has, on its perforation edge region spaced apart from and oppositely arranged relative to the tongue, at least one tongue element formed by a cable segment, which is arranged between the connecting region and another side wall of the receiving recess facing the latter. The connecting region is then spaced apart from the side walls of the receiving recess by the cable on both sides of the receiving recess. It is thus possible to compensate for manufacturing and/or assembly tolerances more effectively. Furthermore, the cable is attached on both sides of the receiving recess between the side walls thereof and the connecting zone, and thus better mechanically connected to the microstructure pieces.
In a preferred embodiment of the invention, the connecting zone has at least one first contact element and one second contact element arranged on sides of the connecting region facing one another, wherein the cable has a first tongue having at least one first counter-contact element on a first perforation edge region facing the first contact element and a second tongue having at least one counter-contact element on a second perforation edge region facing the second contact element, wherein the first tongue is arranged between the connecting region and a first side wall of the receiving recess in such a way that the first contact element contacts the first counter-contact element, and wherein the second tongue is arranged between the connecting region and a second side wall of the receiving recess in such a way that the second contact element contacts the second counter-contact element. Hence tongues can be arranged on both sides of the connecting region between the side wall of the receiving recess and the connecting region, whereby a correspondingly greater number of electrical connections between the strip conductors of the cable and the microstructure is possible.
In the following, illustrative embodiments of the invention are explained in greater detail with reference to the drawing. Shown are:
A microstructure designated in its entirety with 1 comprises a first, approximately disc- or plate-shaped microstructure piece 2, in the surface of which is formed a receiving recess 3. The receiving recess 3 has an approximately rectangular opening and is delimited by side walls 4a, 4b and a floor.
The microstructure 1 further comprises at least one second microstructure piece 5, which is also approximately disc- or plate-shaped and has a connecting region 6 fitting into the receiving recess 3, which is aligned in the receiving recess 3. A segment of the second microstructure piece 5 arranged in elongation of the connecting region 6 is located outside the receiving recess 3.
The connecting region 6 has several contact elements 7a, 7b inside the receiving recess 3, which are connected to electrical conductors not shown in any greater detail in the drawing, which extend on the surface and/or into the interior of the second microstructure piece 5 and which can be connected to a sensor and/or an actuator, an electrode, or another electrical component present on the segment of the second microstructure piece located outside the receiving recess 3.
It can be discerned in
The microstructure 1 has a flat, flexible cable 8 for electrically connecting the contact elements 7a, 7b to an electric circuit such as a measured value acquisition device and/or a driver spaced apart from the microstructure pieces 2, 5. Said cable has a flat substrate layer 9 made of an electrically insulating material, on which are arranged at a distance from the surface of said substrate layer 9 strip conductors 10, each of which is electrically connected to an exposed counter-contact element 11a, 11b on the surface of the cable 8. Preference is given to the substrate layer 9 being composed of a polymer material such as polyamide.
In the cable 8, provision is made of a number of perforations 12 corresponding to the number of receiving recesses 3, which perforations 12 penetrate the cable 8 perpendicular to its plane of extension. However, it is also conceivable for the number of perforations of the cable 8 to be smaller than the number of receiving recesses 3. The cross-sectional dimensions of the perforations 12 are dimensioned in such a way that the connecting region 6 is in each case insertable in its associated perforation 12.
At each edge region 13a, 13b surrounding the individual perforations 12, on the cable 8 is integrally formed at least one tongue 14a, 14b having the counter-contact element 11a, 11b on a site spaced apart from the respective edge region 13a, 13b. It can be discerned in
Adjacent to a first edge region 13a of the perforation 12, the tongue 14a has a curvature that abuts on a segment of the cable 8 running parallel to the surface of the first microstructure piece 2. In
In
In the illustrative embodiment shown in
The tongue element 15 is electrically insulated from the microstructure pieces 2, 5 by the substrate layer 9. The strip conductors 10 and the counter-contact element 11a in each case are spaced apart from the first microstructure piece 2 by the electrically insulating substrate layer 9. In
In
In the illustrative embodiments shown in
The first microstructure piece 2 is manufactured before the microstructure 1 illustrated in
In the manufacturing of the microstructure 1 illustrated in
In the manufacturing of the microstructure 1 illustrated in
In another procedural step, provision is made of the second microstructure piece 5, which has the connecting region 6 fitting into the receiving recess 3 and on which the contact elements 7a are arranged.
Further provision is made of the cable 8. To this end, the flat substrate layer 9 made of the electrically insulating material is deposited on an auxiliary substrate 20 (
In can be discerned in
Afterwards each of the regions of the strip conductors 10 located within the interruptions 23 is covered with a counter-contact element 11a, which projects above the top layer 21 surface facing away from the auxiliary substrate 20 (
As can be discerned in
In the illustrative embodiment shown in
Number | Date | Country | Kind |
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10 2009 037 802.2 | Aug 2009 | DE | national |